X-ray images using films have been widely used heretofore in medical settings. However, the X-ray image using a film provides analog image information, and in recent years, digital radiation detectors such as computed radiography (CR) and flat panel radiation detectors (flat panel detectors: FPDs) have been developed.
The FPDs include a direct system and an indirect system. In the indirect system, a scintillator panel is used for converting a radiation into visible light. The scintillator panel includes, as a constituent element, a scintillator layer containing a phosphor such as cesium iodide, the phosphor emits visible light in response to an applied X-ray, and the emitted light is converted into an electric signal by a TFT or a CCD to thereby convert X-ray information into digital image information.
As the scintillator layer, a columnar crystal formed by vapor-depositing a phosphor is known; however, this type has a problem of productivity. On the other hand, a method in which a coating film of a paste-like phosphor powder is formed to be used as a scintillator layer causes problems that scattering of the emitted light within the coating film increases and image clarity is deteriorated although the method is simple.
In order to suppress a problem of the scattering of the emitted light, in recent years, methods in which a barrier rib for dividing the scintillator layer is formed in advance are proposed (Patent Documents 1 to 3).